Detection of microbial metabolites

Chromogenic 3-Indoxyl choline phosphate compounds of formula (I): wherein R is selected from the group consisting of hydrogen and C1-4 alkyl, such as methyl, ethyl, propyl and butyl while R1, R2, R3, and R4 are independently selected from the group consisting of hydrogen, halogen, cyano, nitro, carboxy, amino, amino substituted with one or two C1-4 alkyl groups, aminomethyl, hydroxy, C1-4 alkoxy, carboxyalkyl, and sulphonyl. These compounds are capable of being cleaved by lecithinase C leading to products which are calorimetrically detectable. The invention provides safe and sensitive detection of potentially pathogenic bacterial activity of such microbes as Clostridium perfringens, Bacillus cereus, Bacillus anthracis, Pseudomonas aeruginosa, Listeria monocytogenes, Heliobacter pylori, Legionella pneumophila, and others in material which may contain such activity typically including physiological samples, goods for consumption, such as food and beverages, and any other potentially infected objects or articles.